a) Field of the Invention
The invention is directed to a regulating vacuum valve. More precisely, the invention is directed to a regulating vacuum valve comprising a valve body with a through-channel, a closure member which is adjustable over a control path between a closed position in which it contacts a valve seat and closes the through-channel and an open position in which it is raised from the valve seat, and an adjusting device which has a drive unit and adjusts the closure member over the control path.
b) Description of the Related Art
There are different known embodiment forms of regulating vacuum valves. For example, U.S. Pat. No. 5,873,562 shows a vacuum regulating valve in which the plate-shaped closure member is displaceable perpendicular to the axis of the through-channel penetrating the valve body. The plate-shaped closure member is swiveled around an axis extending parallel to the axis of the through-channel. This swiveling is carried out in the plane of the plate-shaped closure member. The through-channel is covered to a greater or lesser extent by the closure member for regulating the flow through the through-channel. The valve also has a completely sealed state in which the closure member completely covers the through-channel and an annular sealing member which is mounted so as to be displaceable in the through-channel is adjusted to the closure member.
Since the orifice opened in the regulating area is not symmetric to the axis of the through-channel in this regulating vacuum valve, the gas flow through the valve is asymmetric, which is undesirable in various applications such as in semiconductor technology.
U.S. Pat. No. 6,325,096 B1 shows and describes a regulating valve, including embodiment examples which allow a symmetric flow. For this purpose, band-shaped or plate-shaped parts are moved simultaneously, so that the cross section of the through-channel is made narrower from opposite sides simultaneously and the remaining passage opening is symmetric to the axis of the through-channel. Among the disadvantages of this valve are the parts which are moved simultaneously and which narrow the passage opening and the relatively large constructional size of the valve (considered in the direction vertical to the axis of the passage opening). Also, this valve has no sealed state.
Further, corner valves in which the through-channel through the valve body is bent by 90° are known. The closure member is arranged at a rod which is supported so as to be displaceable in the valve body and which is guided out of the valve body along a sealed displacement leadthrough. The actuating unit for displacing the rod and closure member arranged on the rod is arranged outside the valve body. A corner valve of this kind is described, for example, in DE-OS 34 22 589.
In the valve shown in U.S. Pat. No. 1,699,217, the through-channel through the valve body is also not straight; rather, it is extends in a curved or bent manner through an inner wall of the valve body arranged at an angle to the axis of the inlet opening and outlet opening of the valve body. This inner wall has a passage opening which can be closed and opened by the closure member. The closure member is secured to a rod which again is guided out of the valve body through a displacement leadthrough. The valve can be opened and closed by means of a hand wheel which is arranged outside the valve body.
U.S. Pat. No. 4,577,654 discloses a pipeline valve in which the through-channel penetrates the valve body in a straight line. A valve seat is arranged in the through-channel and a closure member can be adjusted toward this valve seat in the closed state of the valve. For this purpose, two rods are arranged laterally at the closure member and parallel to the axis of the through-channel and penetrate a bore hole in the valve body through a displacement leadthrough. Pistons which are displaceable in cylinder spaces arranged in the valve body are fastened to the other ends of these rods. These cylinder spaces lie in an area of the valve body surrounding the through-channel. This valve has only a completely open and completely closed state. Accordingly, it is not a regulating valve.